This program seeks basic information concerning relations between glucose metabolism and the functional properties of neurons by studying the relatively simple sympathetic and dorsal root ganglia of vertebrates. These ganglia are readily accessible because they lie outside the central nervous system. The initial approach was to determine the effects of neuronal activity on metabolism of glucose and lipids in adult mammalian sympathetic ganglia. More recently the approach has turned to the metabolism during embryonic development that builds the structures needed for synaptic transmission and impulse conduction. The proposed investigations, to be conducted on sympathetic ganglia from chicken embryos, include studies of (a) changes in glucose and lipid metabolism during early development, particularly the biological significance of certain changes recently discovered under this grant, (b) the uptake and oxidation of other possible energy-yielding substrates in the presence of glucose in embryonic ganglia, and (c) effects of changes in the volume and composition of the incubation medium on glucose metabolism. Excised ganglia will be incubated in bicarbonate-buffered media containing labeled glucose or other substances labeled with 14C while continuously recording labeled CO2 output. At the end of incubation constituents of the tissue and products in the bathing medium will be resolved chromatographically and their contents of labeled carbon will be measured. In addition the localization of newly-synthesized lipids will be sought by autoradiography. These studies in the discipline of neurochemistry will contribute to basic knowledge about glucose and lipid metabolism and about embryological development in vertebrate neural tissues, especially the sympathetic nervous system, which is important in cardiovascular control. They thus may be relevant to understanding these processes in various disease states, such as abnormal development, neurological disorders caused by altered glucose supply, and circulatory deficiencies related to malfunction of the sympathetic nervous system.